Developmental Patterns of BCL-2 and BCL-X Polypeptide Expression in the Human Spinal Cord
| Autor: | Mark A. Giovanini, Paul J. Reier, Thomas A. Eskin, Douglas K. Anderson, Anthony T. Yachnis |
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| Rok vydání: | 1998 |
| Předmět: |
Adult
Pathology medicine.medical_specialty Ependymal Cell Cellular differentiation Central nervous system bcl-X Protein Apoptosis Gestational Age Nerve Tissue Proteins Biology Developmental Neuroscience Anterior Horn Cell Neurotrophic factors medicine Humans Neurons Gene Expression Regulation Developmental Cell Differentiation Motor neuron Spinal cord Genes bcl-2 Neuroepithelial cell medicine.anatomical_structure Proto-Oncogene Proteins c-bcl-2 Spinal Cord Neurology Immunology |
| Zdroj: | Experimental Neurology. 150:82-97 |
| ISSN: | 0014-4886 |
| DOI: | 10.1006/exnr.1997.6746 |
| Popis: | The cell death suppressors bcl-2 and bcl-x are developmentally regulated and may modulate physiologic cell death in the central nervous system (CNS). However, little data are currently available on the expression patterns of these polypeptides in the human CNS. We examined the ontogeny of bcl-2 and bcl-x in 12 human spinal cords of gestational ages (GA) between 5 and 39 weeks and in 3 adult cords. Paraffin sections were probed by immunohistochemistry using well-characterized, commercially available antibodies that had been raised against poorly conserved epitopes of these homologous proteins. Between 5 and 10 weeks GA, bcl-2 immunoreactivity was identified in primitive neuroepithelial cells of the ventricular zone. Individual cells of the mantle zone were stained including clusters of early anterior horn cells. Bcl-x immunoreactivity was most prominent in differentiating neurons of the mantle zone and less pronounced in the ventricular zone. Between 10 and 14 weeks GA, bcl-2 staining was observed in cells lining the central canal, neurons of the dorsal horn (especially laminae I and II), and in anterior horn cells. The latter exhibited a range of staining intensities from moderate to nondetectable. Bcl-2 immunoreactivity became markedly reduced between 15 and 25 weeks GA, persisting only in ependymal cells. In contrast, strong bcl-x staining was observed in most neurons throughout development and into adulthood. The period of apparent bcl-2 down-regulation overlaps with a peak in physiologic motoneuron death and the establishment of functional neuromuscular synapses in the human spinal cord. These findings suggest that bcl-2 and bcl-x may both be required for survival of early postmitotic neurons before appropriate synaptic connections have been established. Continued neuronal survival (after bcl-2 is down-regulated) may require persistent bcl-x expression in addition to target-derived neurotrophic factors made available through the formation of appropriate synapses. |
| Databáze: | OpenAIRE |
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